Telephone system.



N6. 857,480. PLTENTED JUNE 18; 1907.-

L. B. NIBMANN.

TELEPHONE SYSTENL. nrmonxon run In. 3,1907.

Suva/u fez fi o LenqsJi/{Fwmann witness THE mun": rnnu 60., musnnlural, n. t.

LEWIS B. NIEMANN, OF STAPLEHURST, NEBRASKA.

TELEPHONE SYSTEM- Specification of Letters Patent.

Patented. J une- 18, 1907.

Application filed March 8,1907- Serial No. 361,336.

To aZZ whom it may concern:

Be it known that I, Lnwrs B. NIEMANN, a

.citizen of the United States, residing at drops at the telephone office or exchange for signaling the exchange operator when a subscriber desires a connection with another subscriber in the system, and it relates more particularly to the employment of an auxiliary drop at the exchange station, whereby a subscriber after completing a conversation with a certain subscriber can quickly and positively signal the operator for connection with another subscriber, and this even should the cord circuit of the operator remain plugged in and the signal drop out out.

In the usual telephone systems having grounded ringing generators and signal drops, the clearing drop often fails to operate, with the result that the operator leaves the cord circuit plugs in the jacks after two subscribers have ceased talking. As long as the plugs remain in neither one of the subscribers can call the operator by the usual signal drops, thus causing a long and tedious delay, until the operator of her own choice tests to see if the line is still busy, and if not, takes out the plugs, whereupon the circuits are restored to normal condition and the waiting subscriber can then signal the operator and et the desired connection.

The principal object of the present inven .tion is to overcome the objections above noted by providin' a supplemental drop which is wound to ave a low resistance so that a current of comparatively low value will insure the operation of the drop, thereby enabling the subscriber to quickly signal the operator by means of the ma neto and thus obviating the usual waiting t at subscribers experience in the common form of party or rural line telephone systems.

With these objects in view and others, as will appear as the description proceeds, the invention comprises the various novel fea tures of construction and arrangement of parts which will be more fully described hereinafter and set forth with particularity in the claims appended hereto.-

In the accompanying drawing, which illustrates one of the embodiments of the invention, the figure shows diagrammatically the supplemental drop circuit in connection with the usual telephone circuit with which it is intended to be employed.

In the present instance, the calling circuits at the switch-board, as well as the speaking and receiving apparatus of the subscribers telephone set have been dispensed with since the same are not essential to an understanding of the present invention.

Referring to the drawing, A and B designate respectively the usual calling and clearout-out drops of a telephone system that are connected by a metallic return circuit with a ringing magneto C at the subscribers stations, one of such magnetos being shown in the present instance. In the line 1 of the circuit between the subscriber s station and the switch-board at which the drops are located, is a push button switch designated generally by 2 that is located at the subscribers station so as to connect the magneto either to ground or to the metallic or line circuit. This switch comprises a spring 3 that normally makes contact with a contact 4, and when actuated, is adapted to engage the contact 5 that is connected to ground by the conductor 6. The spring 3 is permanently connected by the conductor 7 with the magneto 3. The other line 8 of the metallic circuit is connected with the magneto and with the contact or spring 9 on the answer jack 10. This spring is connected with the coil 11 of the signal drop A and thence to ground by the conductor 12. The side 1 of the line circuit is connected with the spring 13 of the jack and when theplug 14 is placed in the jack 10, the metallic circuit is completed through the conductors 15 and 16 of the usual cord circuit and the drop Ais cut out of service. Bridged across the cord circuit by the switch 17 is the clearing-out drop B connected with the switch by conductors 18 and 19.

The system of circuits thus far described is well known and in connection therewith the supplemental signaling device constituting the present invention is employed. This signaling device comprises a supplemental drop D which is of the usual construction and is preferably wound so as to be of very V low resistance. One end of the coil 20 of the through the path formed by the conductor 8,

drop D is connected to the line 18 by the conductor 21, while the other end is connected by the conductor 22 to ground. When the coil is energized, the armature 23 is attracted and the lever 24 raised so as to permit the shutter 25 to fall to signal the operator.

In operation, when a subscriber desires to signal to the exchange operator, the armature of the generator 0 is rotated in the usual manner, while the push button switch is actuated to connect one side of the circuit to ground. The current passes through the conductor 8, through the coil 11 to ground by way of the conductor 12 and back to the generator through the conductor 6, switch spring 3 and conductor 7. Thecurrent passing through the coil 11 attracts the armature of the signal drop A so that the shutter thereof is opened to attract the attention of the operator. The answer plug is then inserted in the jack 10, thereby cutting out the drop A and enabling operator by means of her telephone set to ascertain the number of the subscriber desired. After thus ascertaining the number, operator places the call plug in the jack of the subscriber wanted and the two subscribers are then connected for conversation. After the conversation is finished, the subscribers turn their magnetos so as to supply current for energizing the clearingout drop B. .Under some conditions, the current is not sufficient to energize the clearing-out drop, as for instance, when a number of receivers in the telephone system are down or when the resistance caused by the telephones in circuit is too great. In case one of the subscribers should wish to call the operator immediately after closing conversation with the other subscriber and the clearing out drop should not operate, it is difficult to attract the exchange operators attention. Long waits are often caused, and furthermore, the subscriber more often attempts to signal the operator by actuating the magneto while holding the switch 2 pressed, thereby connecting the magneto to ground. While the circuit is in this condition, it is obvious that the operator cannot be signaled accord ing to the former method employed in magneto systems- With the present. supple mentary' drop D, the subscriber can positively signal to the operator for the reason that a current of very low strength will actuate the said drop. When the subscriber opcrates the magneto and at the same time presses the switch 2, the circuit is completed jack switch 9, tip of theplug 14, and conductor 15, switch 17, conductors 18 and 21, coil 20 and conductor 22 to ground and thence back to the magneto through the grounded conductor 6, switch spring 3 and by current from the ter is grounded.

conductor 7. It will thus be seen that should the usual clearing-out drop fail to operate as to inform the operator that the con versation is completed and that the plug should be taken out to enable the drop A to signal in the usual manner, the supplementary drop will operate to inform the operator that the subscriber previously talking wishes another connection. By connecting the supplementary drop in a grounded circuit, it is obvious that this drop will not operate by a current passing only through the metallic circuit of the system. Thus, when the ole aring-out drop is operated in the usual manner,

the supplementary drop remains closed and the advantages of the construction and of the method of operation will be readily apparent to those skilled in the art to which the invention appertains, and while I have described the principle of operation of the invention, together with the apparatus which I now consider to be the best embodiment thereof, I desire to have it understood that the apparatus shown is merely illustrative and that such changes may be made when desired, as are within the scope of the claims.

Having thus described the invention, What I claim is 1. In a telephone system, the combination of a subscribers station including a source of ringing current, and means for establishing a grounded circuit; with an exchange station including a grounded signal drop, and a clearing-out drop; a circuit connecting 'the subscriber and exchange stations together;

and a supplemental signal at the exchange connected with one side of the metallic circuit and connected with ground to be energized generator when the lat 3. In a telephone system, the combination of a subscribers station including a magneto, a metallic circuit connected therewith, a grounded conductor, and a switch for open ing the metallic circuit and connecting the grounded conductor with the magneto; with a central exchangeincluding a grounded signal drop, a jack connected with the metallic circuit, a cord circuit having a plug for connecting the latter with the metallic circuit In testimony whereof; I afiix my signature in presence of two Witnesses.

LEWIS B. NIEMANN.

leading to the subscribers station and for cutting out the signal drop; and a clearing out drop included in the cord circuit; and a supplemental signal drop of low resistance connected with one side of the circuit includ- Witnesses:

ing the clearing-out drop and also connected WM. MEYER, with the ground. J C. BEAVERS. 

